On Fr, 2024-07-05 at 13:46 -0400, Jim Quinlan wrote:

On Thu, Jul 4, 2024 at 8:56 AM Stanimir Varbanov [off-list ref] wrote:

quoted

Hi Jim,

On 7/3/24 21:02, Jim Quinlan wrote:

quoted

The 7712 SOC adds a software init reset device for the PCIe HW.
If found in the DT node, use it.

Signed-off-by: Jim Quinlan <redacted>
---
 drivers/pci/controller/pcie-brcmstb.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 4104c3668fdb..69926ee5c961 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c

@@ -266,6 +266,7 @@ struct brcm_pcie {
      struct reset_control    *rescal;
      struct reset_control    *perst_reset;
      struct reset_control    *bridge;
+     struct reset_control    *swinit;
      int                     num_memc;
      u64                     memc_size[PCIE_BRCM_MAX_MEMC];
      u32                     hw_rev;

@@ -1626,6 +1627,13 @@ static int brcm_pcie_probe(struct platform_device *pdev)
              dev_err(&pdev->dev, "could not enable clock\n");
              return ret;
      }
+
+     pcie->swinit = devm_reset_control_get_optional_exclusive(&pdev->dev, "swinit");
+     if (IS_ERR(pcie->swinit)) {
+             ret = dev_err_probe(&pdev->dev, PTR_ERR(pcie->swinit),
+                                 "failed to get 'swinit' reset\n");
+             goto clk_out;
+     }
      pcie->rescal = devm_reset_control_get_optional_shared(&pdev->dev, "rescal");
      if (IS_ERR(pcie->rescal)) {
              ret = PTR_ERR(pcie->rescal);

@@ -1637,6 +1645,17 @@ static int brcm_pcie_probe(struct platform_device *pdev)
              goto clk_out;
      }

+     ret = reset_control_assert(pcie->swinit);
+     if (ret) {
+             dev_err_probe(&pdev->dev, ret, "could not assert reset 'swinit'\n");
+             goto clk_out;
+     }
+     ret = reset_control_deassert(pcie->swinit);
+     if (ret) {
+             dev_err(&pdev->dev, "could not de-assert reset 'swinit' after asserting\n");
+             goto clk_out;
+     }

why not call reset_control_reset(pcie->swinit) directly?

Hi Stan,

There is no reset_control_reset() method defined for reset-brcmstb.c.
The only reason I can
think of for this is that it allows the callers of assert/deassert to
insert a delay if desired.

The main reason for the existence of reset_control_reset() is that
there are reset controllers that can only be triggered (e.g. by writing
a bit to a self-clearing register) to produce a complete reset pulse,
with assertion, delay, and deassertion all handled by the reset
controller.

regards
Philipp